Bridge expansion joints are designed to allow for continuous traffic between structures while accommodating movement, shrinkage, and temperature variations on reinforced and prestressed concrete, composite, and steel structures. The Bridge expansion joints stop the bridge from bending out of place in extreme conditions, and also allow enough vertical movement to permit bearing replacement without the need to dismantle the bridge expansion joint. The combination of chlorides and moisture cause a deterioration effect on bridges which can later lead to catastrophic failures of the bridge. Chlorides and moisture penetrate into the concrete and then lead into the steel reinforcing bars; causing the steel reinforcing bars to corrode and which slowly deforms the bridge structure decreasing the overall stability.
The small movement joints currently in use utilize a method commonly called an Asphaltic Plug Joint (APJ). An Asphaltic Plug Joint System is a blended, hot-applied product composed of a formulated polymer modified asphalt binder and selected aggregate. The hot applied material is poured over a foam backer rod which has been inserted into the bridge's expansion joint gap and covered over with a thin steel plate. This method has many times proved to be unreliable for waterproofing. Bridge decks, typically made of concrete are going to expand and contract slightly for a number of reasons, including temperature changes, shrinkage of the concrete, settlement, ice and even the weight of vehicles. Bridge expansion joints are what allow the concrete to naturally expand and contract without cracking. The expansion joints are placed at the end of a bridge where it meets up with the road. These joints give the concrete just enough space to move and avoid concrete cracks. Even though there has been some significant advancement to increase the chances of the bridge not failing due to the deterioration effects from chlorides and moisture though the bridge expansion joints, the existing bridges still show signs of deformation thus showing the ineffectiveness of those methods.
It is therefore an objective of the present invention to provide a method for waterproofing a bridge expansion joint, utilizing the same APJ technique, but eliminating the foam backer rod and thin steel plate, and replacing those elements with the method of the present invention. The method includes a primer and multiple membranes, which are applied and installed on the bridge expansion joint, to provide protection from chlorides and moisture ultimately preventing deterioration and deformation of the bridge structure. The primer and the multiple membranes are applied and installed in a specific method allowing the present invention to effectively waterproof the bridge expansion joint.